Real time video may be sensitive to delays. For example, significant latency in real-time video may lead to reduced quality of experience (QoE). Wireless communication represents a source of delay due to fading and scheduling. For example, with wireless sources and/or destinations, latency may build up at either or both ends from fast fading or intra-coded frame (I-frame) collisions. Additionally, latency may build up in the backhaul of a wireless communications system.
Real time video may contain large I-frames and small predicted picture coded frames (P-frames) alternated periodically in a pre-defined matter. In another example, real time video contains bi-predictive picture frames (B-frames). I-frames may be periodic or based on significant changes in the video, for example a scene change. An I-frame encodes a full picture, similar to a static image. I-frames are coded without reference to other frames. They may be generated by an encoder to create a random access point, which facilitates a decoder beginning to decode from that frame. An I-frame represents one instant in the video stream, and it is desirable for it to be pushed quickly. P-frames indicate incremental changes in the video, contain changes from the previous frame, and require the prior decoding of some other picture(s) to be decoded. I-frames or P-frames may be provided at 1/24 of a second. Both image data and motion vector displacements may be included in a P-frame, with combinations of image and motion data. P-frames may also be known as delta-frames. A P-frame contains less information than an I-frame, and therefore is smaller. A B-frame contains less information than P-frame, and is even smaller. The wireless latency which reduces QoE is largely due to an I-frame being sent and received when the schedule is unable to push it quickly. For example, fading might make the situation unfavorable for pushing I-frames. Also, an I-frame collision occurs when two user equipments (UEs) are coupled to the same communications controller, which tries to push an I-frame to both UEs at the same time. It is also problematic for a communications controller to perform both uplink of an I-frame and downlink of an I-frame at the same time.